Usefulness of S100P in diagnosis of adenocarcinoma of pancreas on fine-needle aspiration biopsy specimens

Even though the cytologic criteria for pancreatic ductal adenocarcinoma (PDA) on fine-needle aspiration biopsy (FNAB) specimens have been well defined, a diagnostic challenge is still present. We immunohistochemically evaluated the diagnostic value of S100P on cell-block and/or smear preparations in 58 cases of FNAB specimens of the pancreas. The 58 cases were divided into 4 groups: 1, 32 cases of PDA; 2, 6 cases with an atypical or "suspicious" diagnosis; 3, 14 cases of benign or reactive ductal epithelium; and 4, 6 cases of endocrine tumor Positive immunoreactivity for S100P was observed in all cases in groups I and 2, whereas only I of 14 cases in group 3 was positive for S100P All cases in group 4 were negative for S100P S100P is a sensitive and specific marker for the detection of PDA on FNAB specimens on cell-block and smear preparations.